Killing Bacteria With Gold Nanodisks And Light

Scientists at the University of Houston have developed a new method for using gold to kill bacteria. According to the research published in Optical Materials Express, the method could one day help hospitals prevent common infections without relying on antibiotics.
The newly developed method builds on other research demonstrating the ability of gold nanoparticles to reflect infrared radiation to destroy close proximity cellular structures, like bacteria and cancer cells. Using this knowledge, the scientists developed a new type of gold nanoparticle with a disk-like shape and porous structure – which improve heating efficiency and stability.

To measure the antibacterial efficacy of the new “nanodisks,” scientists cultivated E. Coli, as well as two additional types of heat-resistant bacteria and added them to a layer of the nanodisks. When light from an infrared laser hits the nanodisks, they instantly reach 356°F – creating a deadly thermal shock, killing all E. Coli in five seconds and all heat resistant bacteria in 25 seconds. This is a marked improvement over other similar sterilization methods, which can take several minutes or hours.

Currently, the researchers are investigating using the nanodisks as a coating for catheters to help reduce the number of urinary tract infections in hospitals. They’re also exploring the potential of integrating the nanodisks into filtration membranes to improve water quality.

Image Source: "Fig. 2" Greggy M. Santos, Felipe Ibañez de Santi Ferrara, Fusheng Zhao, Debora F. Rodrigues, and Wei-Chuan Shih, "Photothermal inactivation of heat-resistant bacteria on nanoporous gold disk arrays," Opt. Mater. Express 6, 1217-1229 (2016)

Spinel Gems vs Other Gems

You've probably met a customer in your shop who on a budget, but looking for jewelry of a certain color. However, colors tend to be exclusively associated with specific types of gems (especially in the mind of the consumer). Emeralds are green, rubies are red, sapphires are blue, etc. But while these gems are spectacularly colored, they can easily break a budget. Luckily, gems under the spinel group can match most of the aesthetic qualities of more expensive gems for a lower cost.

Spinel gems have an interesting history behind them. Before the 18th century, transparent red spinels were thought to be rubies, until modern science was able to differentiate between the two. In fact, many world-famous “rubies” are actually spinels. The Black Prince’s Ruby is set above the Cullinan II (a 317.4 carat diamond cut from the Cullinan – the second largest diamond ever discovered) in the Imperial State Crown as part of the British Crown Jewels. Also part of the Crown Jewels is the Timur Ruby – a 361 carat spinel.

Spinels also have desirable properties in jewelry design. They are durable gemstones that are difficult to chip and scratch. Their colors occur naturally, so no special treatments are needed. Plus, since they are singly refractive, they have a characteristic “fire” similar to diamonds. If you have a customer looking for something affordable, durable, and with nice color - a piece incorporating spinels might be the answer.

Why the ‘Brexit Vote’ in the UK Utterly Rocked Gold Prices

The people of the United Kingdom have voted to leave the European Union in a move being referred to around the globe as “Brexit” (Britain-Exit). The geopolitical ramifications of this move would be out-of-scope for us to analyze on this blog – they are complex and far-reaching… and that’s precisely why the price of gold exploded from $1258 all the way up to $1350 overnight – more than 6%!
Economic uncertainty is a major driving factor in establishing market demand for, and ergo the price of, gold. And Brexit has created a LOT of economic uncertainty. By leaving the EU, the UK is effectively changing the way it does business with rest of the world.

As members of the EU, countries can freely move goods between borders. Under this policy, many companies’ European headquarters are in the UK, where they can control their deals with the whole of Europe. Now, it’s unclear if companies will move their European headquarters somewhere else and maintain only a small presence in the UK, or if they’ll keep their headquarters where they are and create small offices elsewhere. How this affects the significant number of people who live in another country but work in the UK, or vice versa, remains to be seen. Additionally, once the UK formally notifies the EU of its intentions, it must negotiate a trade agreement with the remaining 27 countries in the EU within 2 years – and no one knows how difficult or complex that will be. 

Less than 24 hours after the decision, Prime Minister David Cameron announced that he will resign by October, and the British pound fell from $1.50 to $1.36, an unprecedented drop in such a short period. Right up to voting day, the polls were split 50-50 – so no one could really predict or prepare for the outcome. The global markets are in an historic upheaval, and investors are moving to the #1 safe haven investment: gold. As a result, demand for the metal is skyrocketing and driving the price upward.

If you’re a jeweler or pawnbroker holding on to precious metal scrap, now is the perfect time to sell – and MGS offers the highest payouts in the industry. Even if you are out of state, we can work with you. Contact us for a free quote today!